Large Scale Integration (LSI) technology has been developed along with the development of semiconductor device technology and process technology thereof, and highly integrated memories and high-performance logic integrated circuits have been developed. In a generally used logic circuit, an arithmetic operation is performed by using a binary signal, that is, digital presentation, and the arithmetic operation can be performed for simple numerical calculation at a very high speed. However, a considerable length of time is required for arithmetic operations such as pattern recognition and image processing. Therefore, in recent years, a neural network device that is a computer simulating an information processing method in an animal brain is attracting attention as a device that performs information processing, which conventional LSI arithmetic processing does not handle well, but that an animal such as a human being handles well.